<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
</head>
<body>
	<script type="text/javascript">
		var a=Math;
		// Math = null;
		var age =10;

		Date.prototype.toString = function () {
			return this.getFullYear()+"-"+(this.getMonth()+1)+"-"+this.getDate();
		}

		var person={
			age:10
		}

		// var a=age;
		// a=20;
		// console.log(age);

		var b = person;
		// b=null;
		//  // Cannot set property 'age' of null
		//  // Cannot read property 'age' of null
		// b.age ;//= 20;

		// console.log(person.age);//20,10,10,10
// object

		// 如果是负数 就返回它的 相反数
		// 如果不是返回它本身


		/*function abs(a) {
			if(a<0){
				return -a;
			}else{
				return a;
			}
		}*/


		function abs(a) {
			if(a<0){
				return -a;
			}
			return a;
		}

		var b = abs;

		Math.abs = function (a) {
			return -100;
		}

		/*setInterval(function () {
			alert(1111);
		}, 1000);*/

		// var nn= Date.now();//1970
		// for(var i =0;i<100000;i++){console.log(1)};
		// console.log(Date.now()-nn);

	// new Date()

// var arr=[1,3,3]
// var arr=new Array()
// var obj={}
// var obj=new Object()

	var daxies =  ["零", "壹", "贰", "叁", "肆"];

	function xiao2da(str) {//str = 123324
		var nStr = "";
		for(var i =0;i<str.length;i++){
			nStr+=daxies[str.charAt(i)*1]
		}
		return nStr;
	}
	</script>
</body>
</html>